Flexible plastic tubes are used by a variety of industries to internally convey gasses, liquids, solids or suspensions. There are applications in petroleum, chemical, manufacturing, other industries in which a tubular member's outer surface is used as a means to physically collect (by adsorption) and transfer media from one location to another. An example of this application would be in the skimming of oils, greases, hydrocarbons or other floating non-dissolved solids from the surface of water in a contaminated reservoir. In this application, the collection tube is joined into a long continuous loop, the loop is moved into and out of the pool in a continuous circular path by a mechanical drive system, and the solids and adsorbed hydrocarbon liquids accumulated on the surface of the tube loop are scraped off and collected at the machine before the loop is sent back into the pool. Joining the tube geometry in this type of application are disk-shaped geometries, and looped belt skimmers. However, these latter two configurations are limited in their ability to collect contaminants from large pools due to the fixed nature of their deployment, and the fact that the floating residue to be removed from their surfaces must migrate to the skimmer. Collection tubes in tube skimmers, on the other hand, float on the surface, and by doing so, advantageously migrate over a large area of the pool, vastly increasing the rate by which the pool surface may be cleaned.
Suitable tube materials, by design, should exhibit a high relative degree of flexibility, such that they can easily enter and exit the pool surface from a vertical orientation, and be drawn around positioning pulleys and drive wheels having relatively small radii, such as, for example, less than 25 times the diameter of the tube, 3 to 12 times the diameter of the tube, or 10 to 15 times the diameter of the tube. In short, they should behave similarly to a loosely woven rope, but unlike a rope, a tube's surface is smooth and continuous, and lends itself readily to scraping devices, which are employed to remove the adsorbed contaminants from the tube surface.
A problem exists in that the longer the length of flexible tube floating on the pool surface, the greater the tendency for the tube to flip over itself and entangle. Furthermore, the tube may at times loop up with floating debris. Longer length loops, then, tend to entangle and pull down into knot bundles. These knot bundles then jam the machine entrance and can result in tube or machine breakage. Consequently, tube lengths are sized and cut shorter than would otherwise be desired for many applications. This problem diminishes one of the greatest differentiating qualities of tube skimmers—their ability to float out over substantially all the surface area of the entire pool.
Guide pulleys or posts can be installed to encourage the tube to go out over a larger surface area. However, these are difficult to install and service, and are subject to abrasion and wear.
Compounding the difficulty of solutions in this field are the temperature variations and environmental contaminants that occur in a given outdoor containment pool. Issues with thermal expansion and temperature-related stiffness variation present challenges with selecting tube materials. Various contaminants, such as tree branches, and other rubbish can exacerbate problems with entanglement.
An article of manufacture disclosed herein includes: a tube comprising an elongated, hollow structure, having an inner surface bounding a hollow portion of the tube, and an outer surface defining an exterior surface of the tube; and an elongated stiffening member disposed within the hollow portion of the tube, and extending the length of the tube. The stiffening member has a stiffness of at least 0.5 times that of the tube. The tube is configured to be joined in a looped configuration.
An oil skimmer system disclosed herein includes: a mechanical drive system configured to drive a tube in a continuous loop, and a scraper configured to skim an outer surface of the tube. The tube comprises an elongated, hollow structure, having an inner surface bounding a hollow portion of the tube, and an outer surface defining an exterior surface of the tube. An elongated stiffening member is disposed within the hollow portion of the tube that extends the length of the tube. The stiffening member has a stiffness at least 0.5 times that of the tube. The tube is joined in a looped configuration.
A hollow, spiral wound spring body disclosed herein includes a slideable side and a fixed side, the slideable side and the fixed side each coupled to a mid-section. The slideable side has an inner diameter defining a first inner diameter cross-sectional area; and the fixed side has an inner diameter defining a second inner diameter cross-sectional area. The mid-section comprises an inner diameter cross-sectional area that at least equals a sum of the first and second inner diameter cross-sectional areas.
The articles “a,” “an,” and “the” should be interpreted to mean “one or more” unless the context clearly indicates the contrary.
The term “set” as used herein, should be interpreted to mean a set with at least one member, and not an empty set, unless the context clearly indicates the contrary.